1. Field of the Invention
The present invention relates to a method and apparatus for producing vehicles, by using a plurality of production lines allowing the vehicles to successively pass through a welding step, a coating step and an assembling step in each line.
2. Description of Prior Art
In the past, it has been general that each production line is exclusively used for one or a plurality of types of vehicles.
However, the number of vehicles produced on each production line sometimes extremely increases or decreases according to the need of consumers or the like. If each of the production lines is made for exclusive-use for a particular type of vehicles as in the above-described prior art there occurs a case where one production line may be operating while the other production line must stop operation after having produced a predetermined number of vehicles. This is not preferable in terms of improving the production efficiency.
Further, in another case, the same type of vehicles are produced by a plurality of production lines to keep balance of the numbers of vehicles produced in the production lines. In this case, however, when a model of vehicles is changed, it is necessary to newly provide exclusive-use equipments for the production lines. Particularly, in a welding step, there are many exclusive-use equipments for each type of vehicle. It is therefore an important condition for securing the flexibility of a vehicle production system to suppress an occurrence of exclusive-use investment in the welding step.